A cobpokation of minne



functions more eiliciently) named m. 4, 1930 UNITED STATES PATENT oFFica FRANCIS G. OKIE, OF ST. PAUL, MINNESOTA, ASSIGNOB 'IO MIIVNESOTA MINING 6'; MAIN- UI'ACTUBI'NG COMPANY, OF ST. SOTA PAUL,

MINNESOTA, A CORPORATION OF MINNE- comrosrrn .s'rnuc'runn Ho Drawing. Original No..1,635,801, dated My present invention relates in general to the treatment of material, preferably in sheet form, and more particularly the treatment of material for the purpose of forming or attainin composite structures, of which well known Iorms of abrasives such aswhat is commonl known as sand-paper is an example. he present application is in part a continuation in part a division of my copending applications Serial Nos. 428,287 and 428,289 filed December 4, 1920, and 541,248, filed March 4, 1922, and my Patent Number 1,565,028.

Although I he'reinafter'disclose the practice of my invention in connection with abrasives such as sand-paper, it will be understood thatmy invention, or certain features thereof, has a wider field of utility.

Composite structures of the abrasive type such as sand-paper or emery cloth comprise generally (a) a base of sheet material, which be felted as in the case of paper or woven as in the case of cloth, (1)) a more or less finely comminuted resistant material having abrading properties, such as garnet or corundum, and (021 a binder generally in the form of a glue w to the base.

The abrasive products as produced at present have as incidents certain features among which are aflinity for moisture rendering them substantially inutile in the presence of water or moisture, and cracking, with conse uent exposure of the base, when bent,

he principal objects of my present invention are the provision of a binder which me; the provision of a inder characterized by flexibility without cracking or other undesirable effects; the provision of a binder characterized by extensibility and compressibility to accommodate itself to flexion of the base; the provision of a binder by means of which the desired. adhesive action between it and the base is attained not only efiiciently but also with a desirable degree of acceleration,

and more particularly the provision of a binder in which the drying action will be efl'ective from the contact surface between it and the base outwardly; the provision of a ich serves to bind the abrasive I saturated or part1 than any known to July 12, 1927, Serial No. 670,543, filed. October 24, 1933. Application for reissue filed April 1 9, 1928.

Serial No. 271,895.

binder in which the drying action will be effective from the outer surface inwardly; the provision of a binder characterized by a dr ing action that permits of handling the pro net with a minimum of delay and more particularly such handling without impairment of the superficies of the material; the provision of a binder characterized by an accelerated drying action; the provision of a binder characterized by a limitation of its drying action; the provision of an improved I moisture-proofing treatment for material, and especially material in a sheet form, and more particularly for causing a moisture proofing agent to penetrate into the material; the provision of a moisture-proof composite abrasive structure; the provision of a binder having moisture-proofing functions, and the provision generally of an improved composite abrasive structure and of a method of producing the same together with such other objects and additional'benefits and advantages as may hereinafter appear or be pointed out.

In the employment of my present invention for the production of sandpaper and the like (which I cite for purposes of example) I use as the base a sheet of material (which may be paper or cellulose, or paper or cloth saturated with cellulose or the like) as W111 conveniently serve the employment contemplated, and as the abrasive such comminuted material (which may be crushed garnet) similarly adapted to serve the function in view.

as rosin are peculiarly adapted for the at- '4 tainment of these ends, and ordinary turor synthetic, having the desired characteristics may also be utilized.

In preparing the binder for use, the gum pentine rosin is preferred by me as best atis used in connection with a suitable vehicle which I prefer is of a type such as linseed. oil, China wow otherwise known as tung oil, Perilla oil sh oil, or even a semi-drying 5 oil such as soya-bean oil, for reasons which I will proceed to explain.

In applying a gum preparedwith a vehicle such as China wood oil to one surface of a base of-paper, for example, I have found that the action of the vehicle involves a penetration of the base by the vehicle, for example, China wood oil or any similar drying oil or semi-drying oil.

This results ina moisture-proofing of the material even against the absorption of moisture through the surface opposite to that to which the binder is applied, without at the same time defacing or otherwise undesirably affecting such opposite surface.

This penetration by the vehicle, particularly when coupled with the use of the character of gum pointed out above, carries with a it in such penetration a certain amount of finely divided gum so that a coating and binding action is secured between the fibres of elemenetal portions of the base which thus substantially retards, if it does not entirely prevent, disintegration of the material of the base, in addition to' reventing access of moisture through the 'ase to the plane of contact between the base ,and the main mass 1 f the binder material. 1

The efficient action of the binder may be enhanced in the manufacture of sandpaper if he binderis applied to thebase by the use of pressure and the more or less finely divided abrasive is then applied in such a manner to cause it to adhere to the binder.

In order to accelerate the adhesion between the binder and the base, I have discovered it desirable to use with the binder a modifying agent the action of which is to cause a desiccation of the binder initiated at the-contact surface of the binder with the base and effectiveoutwardly.

In my experience I have discovered that there are a number of materials having a metallic base which are useful for my present purposes, that manganic oxides are peculiarly useful and that borate of manganese best combines siccative energy with the desirable susceptibility to fine grinding.

Due to. the relatively slow drying of binders generally, difliculties are encountered in handling the structure, within aconvenient period because of the soft and sticky character particularly of the exposed surfaces of the binder. This objection I mitigate by associating with the improved binder a substance the actionof which'is to produce an accelerated drying action effective pri-- marily at the exposed surface and working inwardly, and for this purpose I incorporate in the binder a modifying element peculiarly effective in its action as an oxidizing agent binder in holding the abrasive firmly tung oil and as a retarding agent with referenceto the excess absorption of the vehicle by the base.

The substance I have discovered to be particularly adapted for the purpose is carbonate of lead, particularly that which is a ew electrolytic process white lead and whic in my experience is found to be more satisfactory than any other known form of carbonate of lead.

Whereas by itself the white lead adds but relatively little strength to the'binder, in association in the binder with the ,borate of. manganese it intensifies the action of the against the base.

For intesifying the binding action of the binder and for intesifying the drying action of the dryers, and at the same time accomplishing such ends by the employment of a material which is efficacious in holding the mineral elements in suspension without loss of siccative energy or reducing the relative fluidity of the material I have discovered that it is advantageous to employ as part of the binder a paste dryer. This may comprise such mineral substances as sugar of lead and borate' of manganese suspended in a; resinous vehicle but I find it preferable to form the paste dryer so as tohave the minerals contained therein in the form of acetate of lead and resinate of manganese. I have found by experience that the paste dryer should be somewhat in the nature of cheesy butter, rather softer, and of a light brownish grey color.

As an auxiliary in (l) accentuating the adhesion of the binder to the paper, (2) facilthis contains shellac, red lead, litharge, manganese oxid, burnt umber, gum, linseed oil and turpentine q. s.

In order to give the binder the desired body volumetrically considered I preferably employ a varnish consisting largely of China wood .oil, linseed oil, Perill'a oil, or fish oil, boiled until it approaches a solid state. As far as feasible this should be as free as possible from glycerides and fatty acids.

Though I have hereinabove disclosed certain forms of useful dryers having various characteristics, and likewise intcnsifiers, I have discovered that where it is advisable that the siccative action thereof be limited, or at least retarded, under certain conditions, or when producing material for certain purposes, that it is desirable to-in'corporate in the binder a non-drying oil such as castor oil 1 or the like, for such purposes.

Sandpaper made in accordance with the disclosure of my present invention is characterized by great flexibility without any adverse efiects, such as cracking of the binder or base, or loosening of one from the other? Due to the character of binder'for sandpaper and the like which I thus produce, the

adhesion between the base, binder and abrasive is such that an auxiliary bonding material, such as the outermost or top sizing coat,

' customarily .found necessary, may for some as forming the binder itself, is satisfactory,

As an exam 1e of the sizing coat, which also may be emp loyed as a moisture-proof backing, I submit the following formula by weight:

I (A) Treated rosin or resin 2700 Chinawood oil 13962 Mineral dryers 7 9 Thinners 12611 An alternative formula for the same purpose may include the following ingredients y weight:

Treated rosin or resin 2700 Chinawood oil 8100 Mineral dryer 83 Linseed oil 2125 Thinners 8850 The materials used by me as hereinabovedescribed may be varied in character so as to vary the charactertistics of the binder from the standpoint of adhesiveness, non-hygrosco ic, and flexibility; Where such variation in t e use of materialsis employed to produce,

for instance, increased adhesion between the binder and the abrasive, such increase may be attained though possibly at a certain expense 7 in its charactertistic of flexibility. Due, however, to this very same increased adhesiveness, one or more of the outer layersof the base may be removed as by the employment of a base which involves the use of a built up structure having. a number of plies, certain of which ma be removed, or by-- shaving of! part of the 'ckness of the base, or by splitan ordinary sheet of aper. This is m 0 possible in the case 0 my improved binder since I am able to regulatelthe degree of its penetration of'the paper, as desired, and

- so, after soaking, I am able to split an ordinary sheet.

By this process I am enabled to obtain sandpaper characterized by extraordinary thinness and flexibility, in that 'I am able to form sandpaper and the like with-a base so thinthat such product could not be manufactured, if the base originally used were of the thinness ultimately desired.

In my preferred practice with China wood oil and rosin, the adhesive applied is of approximately the following p'roportions by weight and percentages:

China wood oil (tung oil) 106 lbs. 53% Hardened rosin 24 lbs. 12% Linseed oil 2.0 lbs, 10% Dryer 2lbs.' 1% Thinners, say 48 lbs 24% One of the virtues of 'a waterproof binder of the present composition is that it not only penetrates the supporting base, renderingit waterproof, but also is of great utility as contrasted with organic glue (prepared from gelatinous matter) inasmuch as itmay be used with oiled or Waxed paper-which has been Water proofed by treatment with socalled non-drying oil, such as Castor oil, semidrying oil, such as soya-beanoil, or even drying oil such aslinseed oil, or China wood oil,

or fish oil, waxy compounds, such as paraffin, beeswax, carnauba wax,;etc., to which a glue bond will not adhere, but to which my im-.

proved binder'readil y adheres by virtue of its. powers of permeation ofthe base and of commingling with such oiling, greasing or waxing agents In practice, I not only find it convenient to heat the binder to facilitate its application to the back, but also to increase 'its powers of penetration ofthe base.

After the adhesive and abrasive materials are applied, the paper is suitably forced dried (or partially'baked as it is said), to the desired extent by subjectin it in the usual" manner to a temperaturew ich I prefer to control between 130 F. and 150 F., depending upon the degree of hardness desired, an average of say 140 F., being in'my opinion the optimum, a suitable degree of humidity being maintained in the drying chamber to prevent the paper from becoming too' crisp or brittle.-

The binder of my'present invention is noteworthy in that it not only penetrates the paper, etc., of the backing or base, but penetrates, mixes with, or combineswith various oils, greases and vwaxes that are commonly used as waterproofing agents for fabric,and this without weakening,.breakin down, orf ther deleterious mechanical or c emical efects.'

I In cases where the surface of. the fabric is not suitable for the a lication of a smooth coating of the binder V have found it''condesire to secure by Letters Patent is 1- M 1.- The new article of manufacture in the nature of sandpaper, comprising a flexible sheet of fabric, a grit or layerof abrasive particles,- and a waterproof stable adhesive bond, includingmodified Chinawood oil in-;

terposed between said grit and said sheet and-of a nature to adequately maintain its bonding effect in substantially. full measure "throughout theeifective abrading life 'ofgthe abrasive article evenunder sustained application of or immersion in water, but not deleteriously affecting the flexibility of saidsheet when dry. v g 2."The new article of manufacture in the nature'of sandpaper, comprising a' flexible sheet of fabric, a' gut orhlayer of abrasive particles, -and a waterproof stable adhesive bond, including Ghinawood oil and rosin in- I terposed between said grit and said sheet and of a nature to ade uately maintain its bondin effect in su stantially full measure vthroughout the effective abrading life of theabrasivearticle even under sustained application of or immersion in water, but. not vdeletefiou's'sl'y a'fiectinggthe flexibility of said sheet when dry. 1

3. The new article of manufacture in the nature of sandpaper, comprising a flexible.

sheet of fabric, a grit or layer of abrasive particles and waterproof stable adhesive bond, including'Chinawood oil,treated rosin,

and linseed oil inter osed between said grit and said sheet and of niaintain its bondin effect in substantially full measure .throug outthe effective abradang life of the abrasive article even under sustained application of or immersion in -water, .bu t'no t deleteriously affecting the flex- ,ibilityof said sheet when dry.v

4.- The new article of manufacture in the nature of sandpaper, com rising a flexible sheet of fabric, a grit or ayer ofrabrasiveparticles, and waterproof stable adhesive bond, including Chinawood oil, treated rosin, linseed oil and a dryer interposed between said grit and said sheet and of a natureto adequately maintain its bonding effect in substantiallfull measure throughout the effective a rading life of the' abrasive article even under sustained application of or immersion in water, but not deleteriously affecting the flexibility of said sheet when dry.

5. The new article of manufacture in the nature of sandpaper, 'comprising a flexible sheet of fabric, which is moisture-proof, agrit'or' layer of abrasive. particles, and a wa-' a.

tel-proof stable adhesive bond, inch inter? Chmawood oil, rosin o a nature to adequatelyable'b .7

The method of forming an abrasive 1' in water, but not deleteriously affecting the flexibility of said sheet when dry.

6. The new article of manufacture in the nature of sandpaper, comprising a flexible sheet of fabric, which is moisture-proof, a grit or layer of abrasive particles, and a waterproof stable adhesive 'bond, including Chinawood oil, rosin and linseed oil, interposed between said grit and said sheet and penetrating the latter to act as a solvent of and coalesce with the moisture proof material of the fabric and of a nature to adequately maintain its bonding effect in substantially full measure throughout the effective abrading life (if the abrasive article even under sustamed application of or immerslon in water,

but not deleteriously affecting the flexibility of said sheet when dry. f

7. The new article of manufacture in the nature Qf-sand aper comprising a flexible sheet of fabric which contains a moistureproofi'ngoil, a grit or layer of abrasive par- ;ticles and a waterproof stable adhesive bond,

including Chinawood oil and a modifying agent therefor interposed between said grit and said sheet and penetrating the latter and uniting with said moisture-proofing oil'and of a nature to adequatelymaintain its bonding effect in'substantially full measure throu hout the effective abrading life of the abrasive article even under sustained ap lication of or immersion inwater but not de eteriously arfecting the flexibility of said sheet when dry. I 8'. The new article of manufacture in the nature of sandpaper comprisin a flexible sheet of fabric, a gritor layer of a rasive particles, and a waterproof stable adhesive bond, including rosin and a drying oil for rendering same flexible when dry interposed between said grit and said sheet and of an ature to adequately maintain its bonding effect in substanflexibility ofsaid sheet when dry.

9. The method oflforming an abrasive article in the nature of sandpaper or the like which includes impregnating a suitable flexible. sheetof fabr c with a water-insoluble oil, and applying a grit orlayer of abrasive particles to said sheet by 'interposing' a coat of waterproof binder material, which is flex ible when dry, containing an oil miscible the oil of saidsheet whereby to attach said. grit to the sheet and form a]; article, which when dry is flexible, tenacious and impermewater. r

bility of the article.

article the nature of sand-paper which includes as steps thereof, the application to a flexible sheet of fabric of a grit or layer of face of said sheet, which isof a nature when dry to maintain the bonding efie'ct throughout the effective abrading life of the abrasive arm ticle even under sustained application of or immersion in water, and hastening solidification of said adhesive by the application of heatwithout'deleteriously affecting the flexibilityof the article.

11. The method of forming an abrasive are ticle in the nature of sandpaper whichincludes as steps thereof, the application to a flexible sheet of fabric, of a grit or layer of abrasive particles, by interposing a coat of go waterproof material as a stable waterproof adhesive bond between said grit and one surface ofsaid' sheet and allowing said material to penetrate the sheet, and said adhesive being of a nature when dry to maintain the bonding :5 effect throughout the effective abrading life of the abrasive article even under sustained application of or immersion'in water, and

- solidifying said adhesive by the application of heat wthout deleteriously affecting theflexi 12. The method of forming an abrasive article in the nature of sandpaper which-includes as step sthereof, the application to a flexible sheet of fabric which. includes therein. a moisture-proofing agent, of a grit or .layer of abrasive particles 'byinterposing a coat of-waterproof material as a stable water- 'proof adhesive bond between, said grit and' one surface of said sheet, andallowing said to material to penetrate the sheet and unite with the moisture-proofing. agent, said adhesive and agent being of a nature when dry to maintain the bonding effect throughout theeffective abradiiig life of the abrasivearticle even under sustained application of or immersion of water, and solidifying said adhesive by the application of heat without deleteriously afiecting the flexibility. of the article. I v 4 13. The method of forming an abrasive article in thenature of sandpaper which in- ,cludes as steps thereof the application to a.

flexible sheet offabric which includes therein a water-insoluble'wax or oil, of a grit or layer by interposing a coat,

ofabrasive particles of waterproof material as a stable waterproof adhesive bond between said grit and. one surfaceofsaid sheet, allowing said material to enetrate the sheet and unite with such waterinsoluble wax or oil, said bond bein of a na- 4 ture when d to maintain the hon mg efiect throughout t e effective abrading life of the abrasive article even under sustained apphcation of or immersion in .water,'and hastensaid adhesive by the ap ing solidification of plication of heat without'deleteriously affectmg the flexibility of the article.

14. The method of formingan abrasive article in the nature of sandpaper which includes as steps thereof, the application to a flexible sheet of fabric which includes therein a'moisture-proofing agent, of a grit or layer of abrasive particles by interposing a coat of waterproof material containing an oil and a resin as'a stable waterproof adhesive bond between said. grit and one surface of said sheet and allowing said material to penetrate the sheet and unite with em h moisture-proofing agent said oil and said agent being of a nature when dry to maintain the bonding effect throughout the effective abrading life of the abrasive article even under sustained application of or immersion in water, and hastening solidification of said adhesive by the application of heat without deleteriously affecting the flexibility of the article.

15. The method of forming an abrasive article in the nature of sandpaper which 1n-. cludes as .steps thereof, theftreatment of a flexiblesheet of fabric with a water-proofing substance which enters the sheet. applying a grit or layer ofabrasive particles to said.

sheet by interposing a coat of water roof tive abrading life of the article, and hastening solidification of said adhesive by the application of heat at a predetermined temperaturea 16. The method of producing flexible abrasive material which comprises associ ating a suitable base with a coating of a-varnish containing an abrasive and heatmg the same to a temperature about 140 F.

17.1116 method of producing flexible 3 I abrasive sheet material comprisin associat1on of ,a sheet cellulose base, .an an 011, rease or -wax waterproofing agent and a hina wood oil varnish in the form of a coating containing an abrasive ma terial and heat- .ing to a temperature about 140 F.

18, The method of forming an abrasive article in the nature of sandpaper which includes as steps thereof, the application to a flexible sheet of fabric "containing a water-I proofing agent,of a grit or layer of abrasive particles, by interpos ng a coat of waterproof material as a stable waterproof adhesive bond between said grit and one surface of said sheet, which is of a nature to unite with said waterproofin agent, and when dry to maintain t tive life of the a rasive article even under sustained application of orimmersion inwater,

and hastening solidi cation of said adhesive by the "application of heat without deleterie bon in efiect'throu'ghout the efl'ecously .afi'ecting'the flexibility of the article. 19. A new abrasive article in the nature. of

sandpaper which includes a flexible sheet of fabric, a grit or layer of abrasive particles, a coating of heat solidified resinous waterproof material for uniting said grit to said sheet to form a stable waterproof adghesive bond between the grit, and sheet and which is of a nature when dry to maintain the bonding efl'ect throughout substantially the effective abrading life of the abrasive article even under sustained application of or immersion in water. t

20. The method of making flexible abrasive sheet material which consists in combining with a sheet cellulose base, a waterproofing agent impregnated through the fibres thereof, and a separately a plied grit-holding coatin of adhesive, misci le with saidagent ibut di erent therefrom.

'21. The method of making flexible abrasive sheet material which consists in separately applying-to a sheet cellulose base and incomblning therewith anoil impregnated through the fibresthereof and a waterproof grit-holding coating of adhesive, miscible with said oil and co-operating therewith to bond the grit to the impregnated fibres. 7 22. The method of making flexible abram sive sheet material consisting in combinin sive contaimng on a sheet cellulose. base, a non-dryin or semidrying oil impregnated through t e fibres thereof and a grit-holding coating containing drying oil, and baking said base to indurate said drying oil and thereby secure the grit to the base yet leave the'finished abrasive sheet material flexible. a I

23. The method'of making flexible abrasive sheet material consisting in combining with a sheet cellulose base, a non-drying or' semidrying oil impregnated through the fibres thereof anda grit-holding coating of an adhesive which is miscible with said 011, and indu- ,rating said adhesive by the application of heat thus more securely bonding the grit to the impregnated fibres yet leaving the finished a rasive sheet material liable.

24. The method ofmaking exible abrasive sheet material consisting in impregnating a suitable base with a non-drying or semi-drying oily or greasy waterproofing agent, at-

taching the grit thereto by means ofan adhe-f a drying oil and gum and baking to pro uce a tough elastic yet relatively pliable coating securely bonded to the impregnated base.

' 25. The method of making flexible abrasive sheet materialconsistin in combining with a'suitable waterproof, has/e, a grit-holding coatin of a baking varnish and baking the same t us producing a tough elastic and relatively plia le product. 4

26. The method of n sandpaper which inapplying to a paper base a coating "of baking varnish, applying grit thereto, baking the same and varying the deing coating of an adhesive that is miscible in effect throughout the effective abrading 1i e of the abras ve article when 'emplo ed in a water abrading operation andnoteleteriously affecting bonding coat of cnalogous' character to the gree of baking to control the softness of the product paper.

27.. Flexible abrasive sheet material comprising a suitable fibrous base impregnated with a waterproofing agent and a grit-holdwith said agent but different therefrom and which co-operates therewith to bond the grit to the impregnated fibres.

28. Flexible abrasive sheet material comprising a suitable fibrous base impregnated with a non-drying or semi-drying oil, a surface coating of a baked oil-containing adhesive attaching the grit to the impregnated, fibrous base.

29. Waterproof sand-paper comprisin a paper base treated'withan oil and a b ed adhesivecontain'ing a drying oil and a'gum. attaching the it to the base. g a

0. The met od of making flexible abrasive sheet material whichconsistsin combining with a sheet cellulose base a grit-holding coating of adhesiive, and baking the same thereon.

31. Flexible abrasivesheet'material comprising a sheet cellulose base combined with a grit-holding coating of adhesive baked thereon.

32. A new abrasive article in the nature of sandpaper which includes aflexible sheet. of fabric, a grit or layer of abrasive particles, a coatingof heat solidified water-proof material for uniting said it to said sheet to'form a stable water-proo adhesive bond. between r the grit and sheet and which is of a nature when dry to maintain the bonding efl'ect throu hout substantially the efl'e ctive' abrading Iii of the abrasive article even under 'sus tained application of or immersion in water.

33. Waterproof sand-paper-comprisin a paper base treatedwith an oil and a baked adhesive containing a drying oil and a resin, attaching the grit to'the base.

34. The method of making flexible abra-. sive sheet material consisting in combining with a suitable base,'a grit-holding coating of a baking varnish and baking the same'at a temperature above 140 F., thus roducing a tough elastic and relatively pliahle product.

35. The process of making a stable Waterproof abrasive article in the nature of sand- 7 paper or the like which includes applying to a flexible sheet of fabric .a grit or ,layerof abrasive particles, and interposing a water- ,roof bond of a nature to maintain the bond the flexibility of said sheet when dry,and uniting a waterproof auxiliary article by the applicationof heat. 2 In testimony whereof, .I have s n d y e hereunto I 

